I never said there was not a church. There is still a church, and it preaches the pure word of God and administers the sacraments/ordinances as well as provides pastoral care and discipline. We are never without the church or its guidance unless we separate ourselves from it by choice.
Yes, there has always been diversity both within and without the body of Christ. There has always been differences of opinion within the church over various matters and then there have been heresies that had to be confronted and rooted out. Today is not different.
Who is arguing that God has left us alone? I am not. He has sent us the Holy Spirit to dwell in us and guide us and teach us as it says in John 14. It is the anointing of the Holy Spirit, not the teaching of man, that has taught us to “abide in Him” (1 John 2:27).
Who is arguing the absence of a teaching office? I am not. The argument is over what kind of teaching office has been established by God’s Word:
11 And he gave the apostles, the prophets, the evangelists, the shepherds and teachers,12 to equip the saints for the work of ministry, for building up the body of Christ, 13 until we all attain to the unity of the faith and of the knowledge of the Son of God, to mature manhood, to the measure of the stature of the fullness of Christ, 14 so that we may no longer be children, tossed to and fro by the waves and carried about by every wind of doctrine, by human cunning, by craftiness in deceitful schemes. 15 Rather, speaking the truth in love, we are to grow up in every way into him who is the head, into Christ, 16 from whom the whole body, joined and held together by every joint with which it is equipped, when each part is working properly, makes the body grow so that it builds itself up in love. (Ephesians 4)
The goal of every Christian should be that we attain the unity of the faith, but just because we have not achieved perfect unity does not mean there can be no true church at this time. It simply means we all have more maturing to do.